The White House on June 16 released a report it described as the most comprehensive to date on the effects of climate change in the United States. It says farmers and ranchers will be among the most affected. But some farm producers don't see it that way.
Jerry Melillo is one of the lead authors of the new report, and at a recent press conference announcing its release he laid out its conclusions -- in no uncertain terms.

"It is clear that climate change is happening now," he says. "The observed climate changes we report are not opinions to be debated. They are facts to be dealt with."

A section of the report is devoted to agriculture. It notes that many crops benefit from higher levels of carbon dioxide and slightly warmer temperatures. But the relationship is complex and doesn't always work out for the best. For example, warmer temperatures mean winters in the United States are generally getting shorter and milder. That's good for some crops that benefit from a longer growing season. But it also means more pests survive the winter, causing more crop damage and leading to more insecticide use.

Climate change could dry up maple syrup industry

And Melillo points to just one industry that would not benefit from milder winters: maple syrup. Some of America's favorite breakfasts just aren't the same without a sugary stream of the sticky brown liquid. The state of Vermont, in the northeastern United States, is famous for its maple syrup industry. But Melillo says that could be a memory as rising greenhouse gas emissions drive changes in the region's climate.
"As nights in the Northeast have continued to warm, the center of maple syrup production has shifted from the U.S. into Canada," he says. "Production depends on a combination of cold nights and warm days. Under higher emissions, maple trees are expected to decline dramatically in the Northeast, perhaps spelling the end of maple sugaring altogether in this part of the U.S."

But when you check in with maple syrup makers, you find they're not that worried. Jacques Couture is 58, and he was born into a Vermont maple sugaring family. He says if the climate has changed in his lifetime, he hasn't noticed much.
"There hasn't been a dramatic change with whatever's gone on with the weather in the past 50 years," he says. "That's a window of time that I've experienced somewhat, so that's the period I can talk about a little bit. What's the next 50 going to do for us? I don't know. The maple industry is certainly not panicking about it."
Quite the opposite. Couture says Vermont maple syrup makers are investing millions of dollars in new equipment.

Skeptical farmers dismiss threat of climate change
Many farmers and ranchers don't believe climate change is happening at all, or if it is, they're skeptical that humans have anything to do with it. That can cause some friction, because agriculture is not just the victim in climate change -- it's also one of the culprits. Globally, agriculture is responsible for about 15 percent of man-made greenhouse gases. In the United States, it's about 9 percent.

But when experts go out to the field to talk about climate change, some farmers look at them like they're crazy.

Jerry Hatfield is the lead author of the agriculture section of the White House report, and he studies the interaction of plants and the environment for the U.S. Department of Agriculture. He says that when he talks to farmers, it's not that important to talk about whether the planet will warm 1 degree or 10 degrees in the next 50 years, or whose fault it is.

"It's not so much the long-term trends that agriculture needs to be worried about, but the magnitudes of these variations within the growing season," he says.

Motivating farmers by highlighting global warming's effect on profits

A flood can ruin a crop just as well as a drought can, and with more extreme weather on the way, he says, both are more likely. So Hatfield recommends preparing for climate change with an eye to the bottom line.

"Producers really are geared toward profitability," he says. "So this begins to resonate with them."

Make sure you're picking the right varieties of crops for the climate, he tells them. Keep a close eye on your nutrients. Nitrogen oxides are a greenhouse gas, and using too much nitrogen fertilizer is one source. Be vigilant with your weed control and disease scouting. Changing climate could produce some surprises.

Climate experts may face an uphill battle convincing many farmers that climate change will affect them. But focusing on profitability might be an easier way to get them on board.